If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

d76 reversal development

I'm planning on trying my hand at some b&w reversal development. Now I have the components for the bleach solution but i'm still trying to work out the cheapest way to create the 1st and 2nd developers. I have plenty of d76 available and I was wondering if it can be used for either of the developer solutions? If not, what have other people used for effective results? Also any insider tips or notes on the procedure would be greatly appreciated.
Cheers.

Re: d76 reversal development

Originally Posted by f90

I'm planning on trying my hand at some b&w reversal development. Now I have the components for the bleach solution but i'm still trying to work out the cheapest way to create the 1st and 2nd developers. I have plenty of d76 available and I was wondering if it can be used for either of the developer solutions? If not, what have other people used for effective results? Also any insider tips or notes on the procedure would be greatly appreciated.
Cheers.

I have also used HC-110 dilution B (1+31) with the same amounts of sodium carbonate (anhydrous), sodium thiosulfate (pentahydrate) and potassium bromide.
TMax100 35 mm: 12 min at 20 C and more thiosulfate
ADOX Pan 25 35 mm: 6 min at 20 C and less thiosulfate

Development time (1st) is critical and it is different for different emulsions. The amount of thiosulfate is also critical and you have to find the amount that suits you and your film.

rinse, bleach, rinse, clear and fog

I use stannous chloride instead of light to fog the film. Convenient with 35 mm but perhaps not necessary with LF.

2nd developer
I have used a paper developer, Kodak Polymax, dilution 1+9. Time is not critical, ca 6 min at 20 C.
I have not tried HC-110 (dil. B) or d76 (stock) as 2nd developer, but they will work. Add some sodium carbonate (anhydrous), ca 30 g/liter

You can skip the fogging step and the 2nd developer if you use an ordinary sepia toner instead.

Re: d76 reversal development

Almost always a camera negative - positive print process, often with interpositives and internegatives. The final print is made on positive release print material (high density range, clear base). Some later B&W movies have been shot on colour neg and printed in B&W, an example being the Coen's The Man Who Wasn't There (which was also released in colour, as it happens, though that wasn't the director's intention I believe).

Re: d76 reversal development

some bleach solutions will cause harm

The classical bleaching formula is based on potassium dichromate. This chemical as well as all "chromium VI" salts have raised safety concerns for a long time ; you find dichromate in cements, masons and workers in the building industry have been exposed for decades to much higher risks than the amateur photographer using gum bichromate (= dichromate) or classical B&W reversal processes.
However, for those important health & safety reasons, classical dichromate-based B&W reversal kits aimed at the hobbyist like the former German Tetenal B&W reversal kit (that I have sucessfully used in the seventies of the last century) can no longer be sold to the public. But anybody can easily order potassium dichromate from any supplier of chemicals for labs.

FOMA sells a B&W reversal kit with the bleaching bath based on potassium permanganate.
The only problem I know at the hoobyist's level with potassium permanganate is that it takes a long time to dissolve, so the recommendation are to be patient preparing the permanganate-based bath; if some grains of solid permanganate are still present in the bath, you are at risk of getting pinhole-like defects in your slides.

Also, the bleaching bath contains sulphuric acid. When diluted, this acid is corrosive like most acids, hence dangerous; but when concentrated, if you prepare the bath from concentrated sulphuric acid, remember that this product is exceedingly dangerous under concentrated form. Always pour a small quantity of concentrated acid into water, never do the reverse: doing so, the 1-st drop of water falling into concentrated sulphuric acid will immedilately boil and explode, spreading concentrated acid all around ... so be more careful than ever, wear gloves, safety goggles, protective clothes, etc ... this is mandatory.
My understanding is that in B&W kits aimed at the hobbyist, the required sulphuric acid is already diluted and much less dangerous. You do not need concentrated acid at all, only diluted acid is required, hence starting from diluted sulphuric acid, risks are minimal.

Regarding the effects of dichromate on gelatin & film, I have no idea; what I can say is that classical Lumière Autochrome plates (patented in 1903) were based on a dichromate B&W reversal process, those plates nowadays are pretty well preserved.

Regarding various formulae for a do-it-yourself B&W reversal process, there are some recipes posted on MACO's (Mahn & CO, Germany) web site.http://www.mahn.net/OrtPoP.htm
In the compound you'll find a chemical named 'kaliumrhodadid" this is the German name for
potassium thiocyanate K-SCN. This compound is supposed to dissolve silver and help the B&W reversal process in the 1-st developer.

I can confirm from my 1-st experiments with the Tetenal kit that the 1-st development time is critical. It took me several attemps before getting the right time for the 1-st developer, my slides were too dark, I had to increase time.
So do not hesitate to make several tests, do not attempt to make a reversal process on a single roll with your best shots of the year

Re: d76 reversal development

Originally Posted by f90

I have heard that some bleach solutions will cause harm and thin the negatives to an extent, does anyone know any harmless bleach solutions?

No, they will harm the emulsion to some extent. I have ruined films with permangate bleach. The damage can be reduced to acceptable levels though. I try to use as little permanganate as possible and keep the temperature around (or under) 20 C.

My bleach solution (for one 120 or 35mm film or four 4x5):
0,3 - 0,5 g potassium permanganate (more for silver-rich emulsions)
28 g sodium bisulfate (Instead of sulfuric acid. Not harmless but much safer to handle and easier to buy.)
500 ml water (Distilled or de-ionised. Avoid chlorinated water!)